Power management systems for personal computers, in particular for laptop computers are well known in the art. For example, a power management system within a laptop computer monitors the activity of the computer. In case no operations take place, for example no mouse activity and no keyboard activity is detected for a predefined period, a power management system starts a power reducing routine also known as a suspend routine. During the suspend routine a plurality of measurements are taken to save energy. For example, the processor clock speed is slowed down, the hard disk is spun down, not needed peripherals are shut down, a LCD display is turned off, etc. Different stages of low power modes are known. For example, different timings can be set for different devices within the laptop computer system. The display can be turned off after a first time period, whereas the hard disk is spun down after a longer second time period. Many varieties of these low power modes are known in the art. The final low power mode is usually a deep sleep mode in which most of the system components are either shut down completely or put in the lowest possible power consumption mode.
To re-activate a computer system some activity, such as pressing a key, moving a mouse, etc. by a user is necessary. The power management system then restarts the computer and puts the different system components into the same status they had before the suspend routine has been executed. This is called the resume routine. To be able to activate all necessary system components often significant time is necessary. These time periods add up and prevent a instant recovery of the system. Conventional methods of reducing the resume delays is to try to minimize how long each of the resume tasks will take, e.g. reducing the effect of hard disk spin up time by issuing the spin-up command as early as possible. However, the combined time used by the resume routine still adds up and causes significant delays for a user.